This invention relates to a means of treating a damaged vessel in a body and, more particularly, to providing a flexible thin-walled sleeve and a method of inserting the sleeve into the damaged vessel, expanding it against undamaged walls to form a sealed interface to provide a new bridging passage across the damaged area.
The invention deals with a means of treating a blood vessel with defects without expensive and complex surgery. The device can be used for treatment of congenital malformations or for the treatment of acquired abnormalities such as traumatic aneurysms or for therapeutic occlusion of vessels.
Traumatic injuries to blood vessels commonly consist of rupture of the vessel with the formation of hematoma around the vessel, which becomes as it liquifies a pseudoaneurysm without a defined vascular wall. The treatment of these by surgery is often difficult because severe bleeding is encountered as the pseudoaneurysm is explored. Maintaining the patency of the vessel while sealing the leak may be difficult. With the invention the wall may be patched from the inside, preventing further bleeding.
A second type of traumatic injury is a dissection. In this process a partial tear of the vessel is formed so that blood collects between the layers of the vessel wall. The collection of blood eventually narrows the vessel lumen. Surgical repair may be difficult. With the invention, a prosthesis may be placed within the blood vessel without surgery to restore patency to the blood vessel lumen and to prevent further blood from accumulating in the vessel walls.
Aneurysm is another type of vascular problem for which this invention is intended. An aneurysm consists usually of a weakened blood vessel wall which, when exposed to the pressure of circulating arterial blood, expands and in some cases ruptures. Surgical treatment involves complicated and diverse procedures to reinforce the blood vessel wall and to clamp the aneurysm or the vessel from which it originates; or in some cases to occlude the vessel. With the invention, an endoprosthesis is placed so that the vessel wall is reinforced from within and blood is prevented from entering the aneurysm. The result is that the aneurysm thromboses and fibroses thereby ceasing to present a risk to the patient. The patency of the vessel is preserved.
In a fistula there is an anomalous or acquired connection between a vessel containing blood under high pressure such as an artery with a vessel under lower pressure such as a vein. Because of the differences of pressure, blood flows swiftly from the arterial to the venous channel with, in most cases, reduction of the flow to the tissues normally supplied by the artery. To restore normal blood flow, and sometimes to control the abnormal cardiac output, surgical procedures have been devised for treating the fistulae. With the invention, a prosthesis may be place in the artery so that the blood flow is conducted only through the artery and excluded from the fistula. The process includes a way in which this can be done without complex surgery.
Atherosclerosis is a common disease of the blood vessels for which many different types of treatment have been devised. Atherosclerotic narrowing of the blood vessels is often an indication for surgery when the circulation is impeded. Atherosclerotic disease without significant narrowing of a blood vessel may also be an indication for surgery because the roughened vessel wall creates thrombi which detach and enter the blood flow and cause significant complications. Endarterectomy is one type of surgery for these lesions. Recently transluminal angioplasty has been developed as a way of treating these lesions. Surgery is expensive, complicated, and has significant morbidity. Transluminal angioplasty has a significant failure rate and a risk of detaching fatty or thrombus material into the bloodstream, causing complications when they embolize. The invention provides for an alternative to transluminal angioplasty and surgery. The product is placed within the blood vessel. The invention also includes a technique which permits the blood vessel to be dilated with the endoprosthesis in place, restoring the normal diameter of the lumen, while preventing atherosclerotic material from embolizing.
There are numerous other diverse diseases of blood vessels which could be treated by the invention. One example is fibromuscular hyperplasia. In this disease there are numerous bands or constrictions within the vessel limiting the blood flow. With the invention the vessel can be dilated and a new surface created on the inside of the vessel.
The list of indications is not complete or all inclusive, nor is the invention limited to blood vessels. Any hollow body structure could potentially be treated with the invention, nonsurgically, or with reduced surgery. For example, the invention could be used to restore the patency of a ureter, urethra, bile duct, or any body vessel which has been narrowed, weakened, or in any other way requires reinforcement. In some of these applications, valves will be included in the endoprosthesis. A prosthesis with a one-way valve may be used in a ureter to prevent reflux of urine from the bladder, for example. Other body channels include esophagus, bile ducts, urethra, thrachea, enterostomies, and the like. In some of these applications, flanges are included in the prosthesis.
Accordingly, applicants have provided means whereby surgery may be eliminated by simply inserting the prosthesis in the vessel to provide a bridging of the passage and normal circulation in the body.
It is an object of this invention to provide an endoprosthesis for use in a damaged vessel which provides a smooth inner surface and reinforced walls bridging the damaged portion of the vessel.
It is another object of this invention to provide an endoprosthesis consisting of a flexible, thin-walled sleeve for use in repairing the damaged vessel. Either a porous or non-porous prosthesis may be used depending on the nutritional requirements of the blood vessel.
It is a further object of this invention to provide a method of placing a prosthesis consisting of a flexible thin-walled sleeve in a damaged vessel of the body to restore normal flow through the passage.
It is a further object of this invention to provide a method and an apparatus for inserting the prosthesis in a damaged vessel. The method consists of radially collapsing the flexible, thin-walled sleeve for reception in a sheath so that the sleeve may be transported through a vessel to the damaged area in the vessel. Withdrawing the sheath allows the radial expansion of the sleeve to form a bonding interface with the walls of the vessel and thereby provide a renewed surface and passage bridging the damaged area of the vessel.
The objects of the invention are accomplished with a prosthesis and a technique for delivering it to a damaged vessel. The prosthesis is a plastic sleeve which has been molded to fit the interior surface of the blood vessel. The sleeve may have various shapes and forms depending on the indication for treatment of the vessels in which it will be used. The inside diameter of the prosthesis is operated to match the normal inside diameter of the vessel to be treated so that the normal pre-morbid diameter is restored. Ribs, struts, elastics, fabrics, fasteners, or other design characteristics may be included in the prosthesis wall during the molding process to give it specific qualities for a therapeutic indication. In some cases a hollow straight cylinder will be molded, and in other cases a curved cylinder, and in others a y-shaped configuration will be molded. The surfaces of the sleeve will be smooth or textured and the lumen may be uniform or tapered.
The technique for delivering the sleeve to the damaged vessel is essentially a process of radially collapsing the sleeve on a contractable and expandable member. In the contracted condition, the sleeve and the expandable member are transferred to the inside of a sheath. The sheath, the sleeve and the expandable member are then transferred to the inside of the vessel. Withdrawing the sleeve slightly allows the expandable member to expand the sleeve to form a sealing interface between the peripheral outer surface of the two ends of the sleeve and bridge the damaged area of the vessel and thereby provide a new passage in the vessel. The expandable member and sheath are then withdrawn from the vessel and the process is completed.